android - ImageView adjustViewBounds not working

Question

I have an ImageView with android:layout_width=100dp, android:layout_height=wrap_content and android:adjustViewBounds=true

It's source is a 50 x 50 px picture. But the aspect ratio is not preserved - height of the ImageView is 50px, not 100px (i.e. adjustViewBounds is not working). If I have a 200x200px picture it works - width and height are 100px. This code results in a 100px wide and 50px tall picture but the src image is square:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <ImageView
        android:id="@+id/photo"
        android:src="@drawable/icon"
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:scaleType="fitXY"
        android:adjustViewBounds="true" />

</LinearLayout>

Answer 1

The issue is that adjustViewBounds will not increase the size of the ImageView beyond the natural dimensions of the drawable. It will only shrink the view to maintain aspect ratio; if you provide a 500x500 image instead of a 50x50 image, this should work.

If you're interested in the spot where this behavior is implemented, see ImageView.java's onMeasure implementation.

One workaround is to implement a custom ImageView that changes this behavior in onMeasure.